Contaminated suspended sediments toxic to an Antarctic filter feeder: Aqueous- and particulate-phase effects
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journal contribution
posted on 2025-03-19, 00:01authored byNicole HillNicole Hill, CK King, LA Perrett, EL Johnston
Disturbances such as dredging, storms, and bioturbation result in the resuspension of sediments. This may affect sessile organisms that live on hard substrates directly above the sediment. Localized sediment contamination exists around many Antarctic research stations, often resulting in elevated contamination loads in marine sediments. To our knowledge, the potential impact of resuspended contaminated sediments on sessile fauna has not been considered, so in the present study, we assessed the sensitivity of Antarctic spirorbid polychaetes to aqueous metals and to metal-contaminated sediments that had been experimentally resuspended. Worms were first exposed to aqueous metals, both singly and in combination, over 10 d. Spirorbid mortality was tolerant to copper (median lethal concentration [LC50], 570 g/L), zinc (LC50, >4,910 g/L), and lead (LC50, >2,905 g/L); however, spirorbid behavior responded to copper concentrations as low as 20g/L. When in combination, zinc significantly reduced mortality caused by copper. A novel technique was used to resuspend sediments spiked with four concentrations of three metals (up to 450 g/g dry wt of copper, 525 g/g dry wt of lead, and 2,035 g/g dry wt of zinc). The response of spirorbids to unfiltered suspended sediment solutions and filtered solutions (aqueous metal exposure) was measured. Suspended sediments were toxic to filter-feeding spirorbids at concentrations approximating those found in contaminated Antarctica areas. Toxicity resulted both from aqueous metals and from metals associated with the suspended sediments, although suspended clean sediments had no impact. To our knowledge, the present study is the first to show that resuspension of contaminated sediments can be an important pathway for toxicity to Antarctic hard substrate organisms. Based on the present results, current sediment-quality guidelines used in the evaluation of Australian sediments may be applicable to Antarctic ecosystems.
History
Publication title
Environmental Toxicology and Chemistry
Volume
28
Issue
2
Pagination
409-417
ISSN
0730-7268
Department/School
Institute for Marine and Antarctic Studies
Publisher
Setac
Publication status
Published
Place of publication
1010 North 12Th Ave, Pensacola, USA, Fl, 32501-3367
Rights statement
The definitive published version is available online at: http://interscience.wiley.com
Socio-economic Objectives
180404 Biodiversity in Antarctic and Southern Ocean environments